I've just learned after having my pool for 2 seasons (years) that when backwashing, you do so through the waste port. I do not have mine plumed and guess I've been backwashing straight back into the pool. I leave the waste cap on the filter all the time as I've never vacuumed to waste. I had no idea backwashing went through said waste port as well.
I feel it extremely important to note to advanced users on this forum to add "Backwash & Rinse THROUGH THE WASTE PORT" as a step when talking about clearing algae, pool maintenance, etc.
I now know why every so often dirt shoots back into the pool through the return and causes further frustration by having to continually vacuum.